Recording and play reproducing device

ABSTRACT

A recording and playback apparatus includes a video storing device for recording and playing back the sequential scan video signal captured by a sequential scan image pickup device through a light input and output from the sequential scan image pickup device for i frames (i is an integer not smaller than 1) over a period of time T1 (T1 is a positive number). Also included in the recording and playback apparatus is a sequential scan/interlaced scan converting device generating an interlaced scan video signal for m fields (m is an integer not smaller than 2) from each frame of the played back i-frame sequential scan video signal, wherein the interlaced scan video signal is output for i×m fields over a period of time T2 (T2 is a number larger than T1).

TECHNICAL FIELD

The present invention relates to an image pickup apparatus that isadapted to obtain slow motion video, and more particularly to an imagepickup apparatus that is adapted to obtain high definition slow motionvideo.

BACKGROUND ART

In today's television broadcasts of sports programs and other events,slow motion video is heavily used. This technically makes a rapid motioneasier to recognize visually by presenting the rapid motion at a slowerrate and thereby lowering in frequency the high frequency componentsalong time axis to which human vision has a poor response.

On the other hand, in recent years, higher definition video formats thanthe traditional NTSC system have come to be employed as broadcast videoformats, and programs using high definition video are being produced.With this trend, the need has been increasing for apparatuses designedto capture slow motion video in high definition video.

Against this backdrop, image pickup apparatuses of obtaining slow motionvideo have been known in the prior art, including the one described in“A triple Scan Digital Processing Camera for Slow-Motion”, presented atthe 1996 Annual Meeting of The Institute of Image Information andTelevision Engineers, and the one described in Japanese UnexaminedPatent Publication No. 2000-106642.

The entire disclosures of “A triple Scan Digital Processing Camera forSlow-Motion”, presented at the 1996 Annual Meeting of The Institute ofImage Information and Television Engineers, and Japanese UnexaminedPatent Publication No. 2000-106642, are incorporated herein by referencein their entireties.

The prior art image pickup apparatus disclosed in Japanese UnexaminedPatent Publication No. 2000-106642 will be described below.

FIG. 2 shows the configuration of the prior art image pickup apparatusdisclosed in Japanese Unexamined Patent Publication No. 2000-106642.Reference numeral 200 is a light input, 201 is a CCD image sensor whichcaptures an image of a subject, 202 is a CDS/AGC circuit which, using acorrelated double sampling technique, eliminates noise components fromthe image signal supplied from the CCD image sensor 201, and amplifiesit with a suitable gain for output, 203 is an ADC circuit which convertsthe output of the CDS/AGC circuit 202 into digital form, 204 is adigital signal processor (DSP) which applies prescribed video processingto the output of the ADC circuit 203, 205 is a controller which controlsthe entire apparatus, 206 is a memory which temporarily stores a videosignal output from the DSP 204, 207 is a VTR which records and playsback the video signal output from the DSP 204 on a video tape, 208 is aselector switch which selects the video signal from the DSP 204 foroutput when recording the video signal, and selects the video signalplayed back from the VTR 207 for output when playing back the videosignal, 209 is a memory control circuit which controls reading from andwriting to the memory 206, 210 is a display which displays the videosignal according to the output of the selector switch 208, and 211 is anexternal output terminal.

The operation of the thus configured prior art image pickup apparatuswill be described below.

The CCD image sensor 201 has an imaging area consisting of a largenumber of photoelectric conversion elements arranged in a latticepattern, and the charge accumulated by each photoelectric conversionelement through exposure to light is output as an electrical signal.Reading of each photoelectric conversion element from the CCD imagesensor 201 is done a plurality of times within one field period.

The operation for VTR recording will be described below by taking triplespeed image capturing as an example.

First, the controller 205 supplies a readout control signal to eachphotoelectric conversion element at intervals of {fraction (1/180)} of asecond so that the charge of each photoelectric conversion element willbe read out at three times the normal rate. As a result, the chargeaccumulated in each photoelectric conversion element is read out atintervals of {fraction (1/180)} of a second.

When the image signal from the CCD image sensor 201 is supplied, theCDS/AGC 202 eliminates reset noise, etc. from the image signal byapplying noise elimination processing based on the so-called correlateddouble sampling method, amplifies the resulting signal with a suitablegain, and supplies the amplified signal to the ADC 203. The output ofthe CDS/AGC 202 is converted by the ADC 203 into a digital signal.

The DSP 204 performs color separation (RGB) based on the image signalobtained from a complementary color filter array, applies prescribedvideo processing, etc. to the image signal, and supplies the resultingsignal to the selector switch 208. The selector switch 208 is controlledso as to select the output of the DSP 204 at the time of image capturing(recording). As a result, the video signal from the DSP 204 is suppliedfield by field to the memory control circuit 209 via the selector switch208.

The memory control circuit 209 performs control so that the video signalsupplied via the selector switch 208 is temporarily stored in the memory206, and reads out the stored video signal field by field at the normalrecording rate for supply to the VTR 207. The VTR 207 can thus recordimages of the desired subject field by field on a video tape.

The VTR 207 records a plurality of images within one field. In the priorart shown here, since the charge of each photoelectric conversionelement is read out three times in one field period, three images arerecorded one above another as shown in FIG. 3.

An identification signal indicating the number of images recorded in onefield period is also recorded when recording the images on the VTR 207.In the prior art, since there are three images in one field period, anidentification signal indicating n=3 is recorded. The identificationsignal further includes display position information indicating where inthe field the respective n images are recorded and in what sequence theyare recorded. That is, in the prior art, display position informationindicating that three images are recorded in sequence from top to bottomin order of time series is recorded as the identification signal.

Next, the operation for playing back the thus recorded image signal willbe described.

First, the controller 205 performs control to play back the VTR 207. TheVTR 207 plays back the video signal field by filed from the video tape,and supplies the playback signal to the selector switch 208. Whenplaying back the playback signal, the identification signal to be usedfor slow motion playback is also played back together with the videosignal.

In playback, the selector switch 208 is controlled so as to select theplayback signal output from the VTR 207. As a result, the playbacksignal from the VTR 207 is supplied field by field to the display 210and also to the external output terminal 211, via the selector switch208 and the memory control circuit 209.

In this way, the recorded video can be displayed on the display 210 and,when a monitor device of a television receiver or the like is connectedto the external output terminal 211, the recorded image can be displayedon the monitor device.

Slow motion playback of the images recorded on the video tape isperformed in the following manner.

First, the playback signal is read out by the VTR 207 for playback, andis temporarily stored in the memory 206 as it is read out. When readingout the playback signal, the identification signal is also read out.

Next, the memory control circuit 209 reorders the thus stored playbacksignal in order of time series in accordance with the identificationsignal so that the images will be displayed on the display 210, oneimage in each field as shown in FIG. 4. The playback speed at this timeis 1/(n×m) based on the value of n=3 carried in the identificationsignal. Here, the value of m can be suitably chosen by the operator.

That is, in the prior art, the value of n is determined by theidentification signal, and the value of m is determined by operatorselection, thus determining the slow motion playback speed. For example,when m=1 by operator selection, the slow motion playback speed is ⅓ ofthe normal speed, and when m=2, the slow motion playback speed is ⅙ ofthe normal speed. The reordering of images in the memory control circuit209 is done based on the image display position information carried inthe identification signal. In the prior art shown here, since threeimages are recorded within one field in sequence from top to bottom inorder of time series, the memory control circuit 209 reads out the nimages from the memory 206 in sequence from the top for display on thedisplay 210.

The time chart for the above playback operation is shown in FIG. 5. Part(a) of the figure is for explaining the case where the operator hasselected “m=1” for ⅓ speed slow motion playback, while part (b) is forexplaining the case where the operator has selected “m=2” for ⅙ speedslow motion playback.

As shown in FIG. 5, in VTR (RECORDING), a video signal carrying threeimages in each field period, that is, the period from one verticalsynchronization signal VD to the next, is recorded. More specifically,images A, B, and C are recorded in the first field, and images D, E, andF are recorded in the next field.

When playing back the video signal, first the images A to C are read outat the normal rate in the first field, as shown in VTR (PLAYBACK). Theseimages are stored in the memory 206, and then reordered in the memorycontrol circuit 209 in accordance with the identification signal; thethree images are sent to the display 210 repeatedly (n×m) times, thatis, three times.

That is, in the illustrated example, since the value of n is 3, and“m=1” is selected by the operator, the images are played back in slowmotion at 1/(3×1) the normal speed; more specifically, as shown in VTR(PLAYBACK) in FIG. 5(a), the three images A, B, and C are sent to thedisplay 210 repeatedly three times over three fields.

Then, on the display 210, only the image A is displayed in the firstfield, only the image B is displayed in the second field, and only theimage C is displayed in the third field. As a result, each image isdisplayed m times, that is, only once, and only one image in each field.

On the other hand, when the operator has selected “m=2” for ⅙ speed slowmotion playback, then as shown in FIG. 5(b) the three images A to Crecorded in one field period are read out from the VTR 207 and stored inthe memory 206, and then reordered in the memory control circuit 209 inaccordance with the identification signal; these three images are sentto the display 210 in each field period, which is repeated (3×2) times,that is, six times, as shown in VTR (PLAYBACK) in the figure.

Then, on the display 210, only the image A is displayed in the first andsecond fields, only the image B is displayed in the third and fourthfields, and only the image C is displayed in the fifth and sixth fields.As a result, each image is displayed m times, that is, two times insuccession, and only one image in each field.

As described above, in the prior art, video for one field, which shouldnormally be photoelectrically converted every {fraction (1/60)}th of asecond, is photoelectrically converted every {fraction (1/180)}th of asecond, i.e., at three times the normal rate, and slow motion video isobtained through time-axis conversion by using the memory and the VTR.

In the triple speed image pickup apparatus of the prior art, reading ofone-field video from the photoelectrical conversion elements forming thepixels must be done in {fraction (1/180)} of a second. Even in the caseof double speed image capturing, reading from the photoelectricalconversion elements must be done in {fraction (1/120)} of a second.However, in the case of a high definition video CCD image sensordesigned to conform to the video format defining an effective screen of1920 pixels horizontally and 1080 pixels vertically, interlacedscanning, and a field frequency of 59.94 Hz, it is said that doublespeed operation or triple speed operation is difficult to achievebecause of its operating speed problem. That is, the prior art has hadthe problem that high definition video cannot be captured at high speedbecause of the limited operating speed of elements.

Further, when video of an interlaced scanning format is output fordisplay, the prior art image pickup apparatus has had the problem thatthe output images are displaced in the vertical direction. For example,in the operation of FIG. 5(b), “A” is output to the display monitor inthe first and second fields, but since the scanning lines in the firstand second fields are displaced in the vertical direction in interlacedscanning, the displayed images are displaced in the vertical direction.This problem occurs irrespective of the video capturing speed. That is,this problem occurs when the same image is displayed a plurality oftimes for output as a video image conforming to the interlaced scanningformat.

Further, suppose that double speed image capturing for interlacedscanning becomes possible in the future, and that “A” as the video forthe first field is photoelectrically converted in {fraction (1/120)} ofa second and “B” as the video for the second field is photoelectricallyconverted in the next {fraction (1/120)} of a second. Then, suppose thatthe images “A” and “B” as interlaced scanned video images, one displacedfrom the other in the vertical direction in the {fraction (1/60)}-secondperiod, is read out from the CCD image sensor and recorded on the VTR.Here, even if the method of playing back “A” and “B” with the first andsecond fields as a pair is employed in order to avoid the problem thatthe displayed images become displaced in the vertical direction, whenthe images are played back in the order of “A”, “B”, “A”, and “B” forslow motion playback, there occurs the problem that the played backvideo becomes discontinuous with “A” being displayed after “B”, thusmoving backward in time.

DISCLOSURE OF THE INVENTION

In view of the above-enumerated problems, it is an object of the presentinvention to provide a recording and playback apparatus that can producesmooth, high definition slow motion video by preventing an interlacedscan video signal, i.e., slow motion video, from shifting in phase inthe vertical direction or becoming discontinuous video moving backwardin time, and also provide an image pickup apparatus, a recording andplayback method, a recording medium, and a program for use with therecording and playback apparatus.

A first invention provides a recording and playback apparatuscomprising:

-   -   video storing means of recording and playing back the sequential        scan video signal captured by a sequential scan image pickup        means through a light input and output from the sequential scan        image pickup means for i frames (i is an integer not smaller        than 1) over a period of time T1 (T1 is a positive number); and    -   sequential scan/interlaced scan converting means of generating        an interlaced scan video signal for m fields (m is an integer        not smaller than 2) from each frame of the played back i-frame        sequential scan video signal, wherein the interlaced scan video        signal is output for i×m fields over a period of time T2 (T2 is        a number larger than T1).

A second invention provides a recording and playback apparatus as setforth in the first invention, wherein

-   -   when playing back the recorded sequential scan video signal, the        video storing means plays back the recorded sequential scan        video signal of the i frames over the period of time T2, and    -   the sequential scan/interlaced scan converting means generates        the interlaced scan video signal of the m fields from each frame        of the played back sequential scan video signal of the i frames        over the period of time T2.

A third invention provides a recording and playback apparatus as setforth in the first invention, wherein

-   -   when playing back the recorded sequential scan video signal, the        video storing means plays back the recorded sequential scan        video signal of the i frames over the period of time T1, and    -   the sequential scan/interlaced scan converting means generates        the interlaced scan video signal of the m fields from each frame        of the played back sequential scan video signal of the i frames        over the period of time T2.

A fourth invention provides a recording and playback apparatus as setforth in the first invention, wherein

-   -   the sequential scan image pickup means is a sequential scan        video camera with an effective screen of 720 vertical scan lines        and a frame frequency of 59.94 Hz,    -   the sequential scan video signal is a sequential scan video        signal defining an effective screen of 720 vertical scan lines        with a frame frequency of 59.94 Hz, and    -   the interlaced scan video signal is an interlaced scan video        signal defining an effective screen of 1080 vertical scan lines        with a field frequency of 59.94 Hz.

A fifth invention provides a recording and playback apparatus as setforth in the first invention, wherein the video storing means is a harddisk which stores and plays back the captured sequential scan videosignal.

A sixth invention provides a recording and playback apparatus as setforth in the first invention, wherein the video storing means stores theinput sequential scan video signal on a recording medium aftercompressing information of the sequential scan video signal, and playsback the sequential scan video signal by expanding the information readout of the recording medium.

A seventh invention provides an image pickup apparatus which comprises:

-   -   sequential scan image pickup means of capturing an image through        a light input and outputting a sequential scan video signal of i        frames (i is an integer not smaller than 1) over a period of        time T1 (T1 is a positive number);    -   video storing means of recording and playing back the captured        sequential scan video; and    -   sequential scan/interlaced scan converting means of generating        an interlaced scan video signal for m fields (m is an integer        not smaller than 2) from each frame of the played back i-frame        sequential scan video signal, wherein    -   the interlaced scan video signal is output for i×m fields over a        period of time T2 (T2 is a number larger than T1).

According to an eighth invention, the image pickup apparatus of theseventh invention is characterized in that:

-   -   when playing back the recorded sequential scan video signal, the        video storing means plays back the recorded sequential scan        video signal of the i frames over the period of time T2; and    -   the sequential scan/interlaced scan converting means generates        the interlaced scan video signal of the m fields from each frame        of the played back sequential scan video signal of the i frames        over the period of time T2.

According to a ninth invention, the image pickup apparatus of theseventh invention is characterized in that:

-   -   when playing back the recorded sequential scan video signal, the        video storing means plays back the recorded sequential scan        video signal of the i frames over the period of time T1; and    -   the sequential scan/interlaced scan converting means generates        the interlaced scan video signal of the m fields from each frame        of the played back sequential scan video signal of the i frames        over the period of time T2.

A tenth invention provides a recording and playback method whichcomprises:

-   -   video storing step of recording and playing back the sequential        scan video signal captured by a sequential scan image pickup        means through a light input and output from the sequential scan        image pickup means for i frames (i is an integer not smaller        than 1) over a period of time T1 (T1 is a positive number); and    -   sequential scan/interlaced scan converting steps of generating        an interlaced scan video signal for m fields (m is an integer        not smaller than 2) from each frame of the played back i-frame        sequential scan video signal, wherein the interlaced scan video        signal is output for i×m fields over a period of time T2 (T2 is        a number larger than T1).

An eleventh invention provides a program for causing a computer tofunction in the recording and playback apparatus of the first inventionas:

-   -   video storing means of recording and playing back the sequential        scan video signal captured by a sequential scan image pickup        means through a light input and output from the sequential scan        image pickup means for i frames (i is an integer not smaller        than 1) over a period of time T1 (T1 is a positive number); and    -   sequential scan/interlaced scan converting means of generating        an interlaced scan video signal for m fields (m is an integer        not smaller than 2) from each frame of the played back i-frame        sequential scan video signal.

A twelfth invention provides a recording medium holding thereon theprogram of the eleventh invention and processable by a computer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the configuration of an image pickupapparatus according to one embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of an image pickupapparatus according to the prior art.

FIG. 3 is a diagram for explaining how video is recorded on a VTR in theimage pickup apparatus of the prior art.

FIG. 4 is a diagram for explaining how slow motion video is played backin the image pickup apparatus of the prior art.

FIG. 5 is a time chart illustrating the operation of the image pickupapparatus of the prior art.

DESCRIPTION OF REFERENCE NUMERALS

-   1. Sequential Scan Image Pickup Means-   2. Video Storing Means-   3. Sequential Scan/Interlaced Scan Converting Means-   100. Light Input-   101. Video Camera-   102. Information Compressing Circuit-   103. Hard Disk-   104. Information Expanding Circuit-   105. Sequential Scan/Interlaced Scan Conversion Circuit.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below withreference to the drawings.

(Embodiment 1)

FIG. 1 shows an image pickup apparatus according to a first embodimentof the present invention. In FIG. 1, reference numeral 1 is a sequentialscan image pickup means, 2 is a video storing means, 3 is a sequentialscan/interlaced scan converting means, 100 is a light input, 101 is asequential scan video camera with an effective screen of 720 verticalscan lines and a frame frequency of 59.94 Hz, 102 is an informationcompressing circuit, 103 is a hard disk, 104 is an information expandingcircuit, and 105 is a sequential scan/interlaced scan conversion circuitwhich converts a sequential scan video signal defining an effectivescreen of 720 vertical scan lines into an interlaced scan video signaldefining an effective screen of 1080 vertical scan lines.

The sequential scan image pickup means 1 in the present embodiment is anexample of the sequential scan image pickup means of the presentinvention, the video storing means 2 in the present embodiment is anexample of the video storing means of the present invention, and thesequential scan/interlaced scan converting means 105 in the presentembodiment is an example of the sequential scan/interlaced scanconverting means of the present invention.

The operation of the thus configured image pickup apparatus will bedescribed below.

First, the sequential scan video camera 101 used as the sequential scanimage pickup means 1 captures the light input 100 and outputs asequential scan video signal. As for the video format, the number ofeffective scan lines in the vertical direction is 720, the total numberof scan lines is 750, the number of effective pixels in the horizontaldirection is 1280, the total number of pixels in the horizontaldirection, including those in horizontal blanking, is 1650, and theframe frequency is 59.94 Hz; the sequential scan video signal is outputin the form of a digital signal consisting of a luminance signal Ysampled by a clock of 74.176 MHz with 10-bit quantization and two colordifference signals Pb and Pr sampled at 37.088 MHz with 10-bitquantization.

Next, the information compressing circuit 102 compresses the inputsequential scan video signal in accordance with a JPEG scheme, andwrites the compressed sequential scan video signal to the hard disk 103.On the other hand, the compressed sequential scan video signal read fromthe hard disk 103 is expanded in accordance with the JPEG scheme by theinformation expanding circuit 104 to reconstruct the sequential scanvideo signal.

Next, the sequential scan/interlaced scan conversion circuit 105 as thesequential scan/interlaced scan converting means 3 converts thesequential scan video signal defining the effective screen of 720vertical scan lines into the interlaced scan video signal defining theeffective screen of 1080 vertical scan lines; here, the video signal forone frame of sequential scanning is converted into the video signal fortwo fields of interlaced scanning.

Here, the hard disk 103 is controlled so that the period over which oneframe of the sequential scan video signal is read out is twice as longas the period over which one frame is written. That is, in the videostoring means 2, the number of frames per unit time when reading thesequential scan video signal for playback is one half of the number offrames per unit time when writing the captured sequential scan videosignal for recording; therefore, when a sequential scan video signalhaving a frame frequency of 59.94 Hz is written, it is read out as asequential scan video signal of 29.97 Hz. By converting this readoutsignal from sequential scan to interlaced scan, the sequential scanvideo signal for one frame is converted into the interlaced scan videosignal for two fields. This means that the 29.97-Hz sequential scanvideo signal is converted into an interlaced scan video signal having afield frequency of 59.94 Hz.

That is, since an image captured at a rate of 1/59.94 of a second (oneframe of sequential scanning) is converted into an image at a rate of1/29.97 of a second (two fields of interlaced scanning), ½ speed slowmotion can be achieved.

Alternatively, when reading the 29.97-Hz sequential scan video signalfrom the hard disk 103, control may be performed so that the same frameis read out twice in succession. By converting this readout signal fromsequential scan to interlaced scan, the sequential scan video signal forone frame written to the hard disk 103 is converted into the interlacedscan video signal for four fields.

That is, since an image captured at a rate of 1/59.94 of a second (oneframe of sequential scanning) is converted into an image at a rate of1/14.99 of a second (four fields of interlaced scanning), ¼ speed slowmotion can be achieved.

The above description has been given by dealing with the case in whichthe sequential scan/interlaced scan conversion circuit 105 converts thevideo signal for one frame of sequential scanning into the video signalfor two fields of interlaced scanning. However, depending on the design,the sequential scan/interlaced scan conversion circuit 105 may convertthe video signal for one frame of sequential scanning into the videosignal for only one field of interlaced scanning at a time. In thiscase, to obtain the interlaced scan video signal for one more field, thesequential scan video signal for the same one frame must be output fromthe hard disk 103 one more time.

In this case, the sequential scan video signal read from the hard disk103 is a video signal of 59.94 Hz, but since the same sequential scanvideo signal is read out for two frames in succession, the obtained59.94-Hz interlaced scan video signal provides ½ speed slow motion. Whenthe same sequential scan video signal is read out for four frames insuccession, ¼ speed slow motion can be achieved.

In this way, the sequential scan image pickup means 1 captures an imagethrough the light input 100, and outputs the sequential scan videosignal for i frames (i is an integer not smaller than 1) over a periodof time T1 (T1 is a positive number). Then, the video storing means 2records and plays back the sequential scan video signal output from thesequential scan image pickup means 1.

Then, the sequential scan/interlaced scan conversion circuit 105generates an interlaced scan video signal for m fields (m is an integernot smaller than 2) from each frame of the played back i-framesequential scan video signal. The thus generated interlaced scan videosignal is output for i×m fields over a period of time T2 (T2 is a numberlarger than T1). Accordingly, T1/T2 speed slow motion can be achieved.

In the above case, the sequential scan image pickup means 1 captures animage through the light input 100, and outputs the sequential scan videosignal for i frames (i is an integer not smaller than 1) over the periodof time T1 (T1 is a positive number); when playing back the recordedsequential scan video signal, the video storing means 2 plays back therecorded i-frame sequential scan video signal over the period of time T2(T2 is a number larger than T1), and the sequential scan/interlaced scanconverting means 3 generates the interlaced scan video signal for mfields from each frame of the played back i-frame sequential scan videosignal over the period of time T2. That is, the video produced from thesequential scan video signal played back in the video storing means 2 isslower in time than the video produced from the sequential scan videosignal output from the video camera 101 for recording. The videoproduced from the sequential scan video signal played back in the videostoring means 2 and the video produced from the interlaced scan videosignal converted by the sequential scan/interlaced scan converting means3 are of the same speed.

In an alternative example, the sequential scan image pickup means 1captures an image through the light input 100, and outputs thesequential scan video signal for i frames (i is an integer not smallerthan 1) over the period of time T1 (T1 is a positive number); here, whenplaying back the recorded sequential scan video signal, the videostoring means 2 may play back the recorded i-frame sequential scan videosignal over the period of time T1, and the sequential scan/interlacedscan converting means 3 may generate the interlaced scan video signalfor m fields from each frame of the played back i-frame sequential scanvideo signal over the period of time T2 (T2 is a number larger than T1).That is, they may be configured so that the video produced from thesequential scan video signal output from the video camera 101 forrecording and the video produced from the sequential scan video signalplayed back in the video storing means 2 are of the same speed, and sothat the video produced from the interlaced scan video signal convertedby the sequential scan/interlaced scan converting means 3 is slower thanthe video produced from the sequential scan video signal played back inthe video storing means 2. This corresponds, for example, to the case inwhich a VTR is used in place of the hard disk 103. In this case, aseparate memory has to be used to temporarily store the sequential scanvideo signal played back from the VTR, as previously explained in thedescription of the prior art.

The thus configured and operating image pickup apparatus of the presentinvention comprises the sequential scan image pickup means 1 ofcapturing an image through the light input and outputting the sequentialscan video signal, the video storing means 2 of storing and playing backthe sequential scan video signal obtained from the sequential scan imagepickup means 1, and the sequential scan/interlaced scan converting means3 of converting the sequential scan video signal for one frame playedback by the video storing means 2 into the interlaced scan video signalfor two fields; in this configuration, since the video read out andplayed back by the video storing means 2 is sequential scan video, ifthe video of the same frame is read out any number of times, thephenomenon of the video moving backward in time does not occur. Further,since the sequential scan/interlaced scan converting means 3 performsthe conversion by considering the phase shift in the vertical directionthat occurs between the first and second fields, smooth slow motionvideo free from the vertical phase shift can be achieved.

Furthermore, since the sequential scan video camera 101 with aneffective screen of 720 vertical scan lines and a frame frequency of59.94 Hz is used as the sequential scan image pickup means 1, and sincethe sequential scan/interlaced scan conversion circuit 105 whichconverts the sequential scan video signal defining an effective screenof 720 vertical scan lines into the interlaced scan video signaldefining an effective screen of 1080 vertical scan lines is used as thesequential scan/interlaced scan converting means 3, smooth videocomparable to the slow motion video generated from the video captured attwice the normal speed can be achieved even in the case of a highdefinition video format.

Generally, in the case of a video camera that, by using a CCD imagesensor, captures interlaced scanning video of an effective screen of1080 vertical scan lines and a field frequency of 59.94 Hz, the CCDimage sensor which has photoelectric conversion elements forming aneffective screen of 1920 pixels horizontally and 1080 pixels verticallyis operated with a clock of 74.176 MHz, but at the present state oftechnology, it is difficult to operate the CCD image sensor at twicethat clock frequency, i.e., at 148 MHz; further, even if a drive circuitrequiring a large current is provided, performance problems will occuras sufficient S/N ratio and sensitivity cannot be obtained.

By contrast, when the sequential scan image pickup means of the presentinvention is used, smooth slow motion video can be achieved becauseimages can be captured at double speed while operating the CCD imagesensor at the clock frequency of 74.176 MHz.

In the image pickup apparatus described in the section of the prior art,a VTR was used as the video storing means, but by using a hard disk asthe video storing means, it has become possible to output the video ofthe same frame successively any number of times without requiring theuse of a separate memory. The hard disk has excellent random accessability and can easily output the video of the same frame successively aplurality of times; however, in the case of the VTR, this is difficultto achieve, and therefore, a separate memory circuit has had to beprovided. On the other hand, in the present invention, the video can beread out and played back by using only the hard disk, without requiringthe provision of a separate memory circuit.

Furthermore, in the video storing means, since the incoming sequentialscan video signal is compressed and recorded as compressed informationon the recording medium, and the sequential scan video signal is playedback by expanding the information read out of the recording medium, ithas become possible to lower the data transfer rate to the recordingmedium. Generally, a high definition video signal has a larger amount ofinformation than conventional video signals such as the NTSC videosignal, and requires the provision of a large capacity storage medium inthe video storing means and a high transfer rate. However, by employinginformation compression/expansion schemes, the transfer rate can belowered, and the apparatus can thus be implemented easily.

In the present embodiment, when the number of frames of the sequentialscan video signal written and stored in the video storing means isdenoted by j, and the number of frames of the sequential scan videosignal read out for playback is denoted by k, the sequential scan videosignal is read out for playback at a rate of k=1 or k=2 for j=1, toachieve ½ or ¼ speed slow motion video, but it will be appreciated that,by varying the ratio j:k, speed conversion at various ratios can beachieved.

In the present embodiment, a hard disk is used as the video storingmeans, but instead, a large capacity semiconductor memory may be used.

Furthermore, in the present embodiment, a sequential scan video camerawith an effective screen of 720 vertical scan lines and a framefrequency of 59.94 Hz is used as the sequential scan image pickup means,but alternatively, a sequential scan video camera with an effectivescreen of 480 vertical scan lines and a frame frequency of 59.94 Hz maybe used, and the sequential scan/interlaced scan converting means may beconstructed using a circuit that converts the sequential scan videosignal of an effective screen of 480 vertical scan lines and a framefrequency of 59.94 Hz into an interlaced scan video signal. In thiscase, though the resolution is lower than that achieved by the presentembodiment, the same effect can be obtained for the conversion along thetime axis, and smooth slow motion video can be achieved.

Further, in the present embodiment, a sequential scan video camera witha frame frequency of 59.94 Hz is used as the sequential scan imagepickup means, and a sequential scan/interlaced scan conversion circuitthat converts the sequential scan video signal of a frame frequency of59.94 Hz into the interlaced scan video signal of a field frequency of59.94 Hz is used as the sequential scan/interlaced scan convertingmeans, but alternatively, a sequential scan video camera with a framefrequency of 50 Hz may be used as the sequential scan image pickupmeans, and a sequential scan/interlaced scan conversion circuit thatconverts the sequential scan video signal of a frame frequency of 50 Hzinto an interlaced scan video signal of a field frequency of 50 Hz maybe used as the sequential scan/interlaced scan converting means; in thatcase also, a similar effect can be obtained, and smooth slow motionvideo can be achieved.

As described above, according to the present embodiment, with theprovision of the sequential scan image pickup means, the video storingmeans of storing and playing back the sequential scan video signalobtained from the sequential scan image pickup means, and the sequentialscan/interlaced scan converting means of converting the sequential scanvideo signal for one frame played back by the video storing means intothe interlaced scan video signal for two fields, a marked effect ofbeing able to produce smooth, high definition slow motion video can beobtained by preventing the interlaced scan video signal output from thesequential scan/interlaced scan converting means, i.e., the slow motionvideo, from shifting in phase in the vertical direction or becomingdiscontinuous video moving backward in time.

The present invention includes a program for causing a computer to carryout the functions of all or part of the means (or devices, elements,etc.) of the recording and playback apparatus of the invention describedabove, wherein the program operates in collaboration with the computer.

Further, the present invention includes a recording medium holdingthereon a program for causing a computer to carry out all or part of thefunctions of all or part of the means (or devices, elements, etc.) ofthe recording and playback apparatus of the invention described above,wherein the program which is readable by the computer is read by thecomputer and carries out the functions in collaboration with thecomputer.

Here, “part of the means (or devices, elements, etc.)” of the presentinvention described above refers to one or more of the plurality ofmeans, and “part of the steps (or processes, operations, effects, etc.)”of the present invention described above refers to one or more of theplurality of steps.

Further, “the functions of the means (or devices, elements, etc.)” ofthe present invention described above refers to the functions of all orpart of the means, and “the operation of the steps (or processes,operations, effects, etc.)” of the present invention described aboverefers to the operation of all or part of the steps.

In one utilization mode of the program of the present invention, theprogram may be recorded on a recording medium readable by a computer,and be operated in collaboration with the computer.

In another utilization mode of the program of the present invention, theprogram may be transmitted through a transmission medium, be read by acomputer, and be operated in collaboration with the computer.

The data structure of the present invention includes a data base, dataformat, data table, data list, data type, etc.

The recording medium includes a ROM or the like, and the transmissionmedium includes a transmission medium such as the Internet, light waves,radio waves, or sound waves.

The computer of the present invention described above is not limited topure hardware such as a CPU, but may include firmware, an OS, and even aperipheral device.

As described above, the configuration of the present invention may beimplemented in software or in hardware.

POTENTIAL FOR UTILIZATION IN INDUSTRY

As is apparent from the above description, the present invention is ableto provide a recording and playback apparatus that produces smooth, highdefinition slow motion video by preventing the interlaced scan videosignal output from the sequential scan/interlaced scan converting means,i.e., the slow motion video, from shifting in phase in the verticaldirection or becoming discontinuous video moving backward in time, andalso provide an image pickup apparatus, a recording and playback method,a program, and a recording medium for use with the recording andplayback apparatus.

1. A recording and playback apparatus comprising: video storing means ofrecording and playing back the sequential scan video signal captured bya sequential scan image pickup means through a light input and outputfrom the sequential scan image pickup means for i frames (i is aninteger not smaller than 1) over a period of time T1 (T1 is a positivenumber); and sequential scan/interlaced scan converting means ofgenerating an interlaced scan video signal for m fields (m is an integernot smaller than 2) from each frame of a played back i-frame sequentialscan video signal, wherein the interlaced scan video signal is outputfor i×m fields over a period of time T2 (T2 is a number larger than T1).2. A recording and playback apparatus as set forth in claim 1, whereinwhen playing back the recorded sequential scan video signal, the videostoring means plays back the recorded sequential scan video signal ofthe i frames over the period of time T2, and the sequentialscan/interlaced scan converting means generates the interlaced scanvideo signal of the m fields from each frame of the played backsequential scan video signal of the i frames over the period of time T2.3. A recording and playback apparatus as set forth in claim 1, whereinwhen playing back the recorded sequential scan video signal, the videostoring means plays back the recorded sequential scan video signal ofthe i frames over the period of time T1, and the sequentialscan/interlaced scan converting means generates the interlaced scanvideo signal of the m fields from each frame of the played backsequential scan video signal of the i frames over the period of time T2.4. A recording and playback apparatus as set forth in claim 1, whereinthe sequential scan image pickup means is a sequential scan video camerawith an effective screen of 720 vertical scan lines and a framefrequency of 59.94 Hz, the sequential scan video signal is a sequentialscan video signal defining an effective screen of 720 vertical scanlines with a frame frequency of 59.94 Hz, and the interlaced scan videosignal is an interlaced scan video signal defining an effective screenof 1080 vertical scan lines with a field frequency of 59.94 Hz.
 5. Arecording and playback apparatus as set forth in claim 1, wherein thevideo storing means is a hard disk which stores and plays back thecaptured sequential scan video signal.
 6. A recording and playbackapparatus as set forth in claim 1, wherein the video storing meansstores the input sequential scan video signal on a recording mediumafter compressing information of the sequential scan video signal, andplays back the sequential scan video signal by expanding the informationread out of the recording medium.
 7. An image pickup apparatus whichcomprises: sequential scan image pickup means of capturing an imagethrough a light input and outputting a sequential scan video signal of iframes (i is an integer not smaller than 1) over a period of time T1 (T1is a positive number); video storing means of recording and playing backthe captured sequential scan video; and sequential scan/interlaced scanconverting means of generating an interlaced scan video signal for mfields (m is an integer not smaller than 2) from each frame of theplayed back i-frame sequential scan video signal, wherein the interlacedscan video signal is output for i×m fields over a period of time T2 (T2is a number larger than T1).
 8. The image pickup apparatus of claim 7 ischaracterized in that: when playing back the recorded sequential scanvideo signal, the video storing means plays back the recorded sequentialscan video signal of the i frames over the period of time T2; and thesequential scan/interlaced scan converting means generates theinterlaced scan video signal of the m fields from each frame of theplayed back sequential scan video signal of the i frames over the periodof time T2.
 9. The image pickup apparatus of claim 7 is characterized inthat: when playing back the recorded sequential scan video signal, thevideo storing means plays back the recorded sequential scan video signalof the i frames over the period of time T1; and the sequentialscan/interlaced scan converting means generates the interlaced scanvideo signal of the m fields from each frame of the played backsequential scan video signal of the i frames over the period of time T2.10. A recording and playback method which comprises: video storing stepof recording and playing back the sequential scan video signal capturedby a sequential scan image pickup means through a light input and outputfrom the sequential scan image pickup means for i frames (i is aninteger not smaller than 1) over a period of time T1 (T1 is a positivenumber); and sequential scan/interlaced scan converting step ofgenerating an interlaced scan video signal for m fields (m is an integernot smaller than 2) from each frame of the played back i-framesequential scan video signal, wherein the interlaced scan video signalis output for i×m fields over a period of time T2 (T2 is a number largerthan T1).
 11. A program for causing a computer to function in therecording and playback apparatus of claim 1 as: video storing means ofrecording and playing back the sequential scan video signal captured bya sequential scan image pickup means through a light input and outputfrom the sequential scan image pickup means for i frames (i is aninteger not smaller than 1) over a period of time T1 (T1 is a positivenumber); and sequential scan/interlaced scan converting means ofgenerating an interlaced scan video signal for m fields (m is an integernot smaller than 2) from each frame of the played back i-framesequential scan video signal.
 12. A recording medium holding thereon theprogram of claim 11 and processable by a computer.